A system for applying suction to a wound is provided, including a suction source for providing suction to a conduit operatively associated with the wound to communicate suction to the wound, a vent in fluid communication with the conduit to provide a reference airflow into the conduit when the system is in operation, such that a loss of suction at the wound is indicated by deviation from the reference airflow, and a waste collector canister between the wound and the suction source for collecting liquids aspirated from the wound, wherein the canister includes one or more disks containing gelling agent.